One common feature among the insect vector species is that they must rely on some form of chemical communication (olfaction) to initiate and/or mediate key behaviors. Recently, hormonal peptides and their genes have become prime targets for research on the regulation of olfactory processes because they are important messengers that mediate coordination among various tissues involved in the communication system. Although the peptides themselves may not be used directly if ingested in pest control techniques, knowledge of the corresponding genes could open up many exciting avenues of attack. A new peptide involved in the hormonal control of pheromone production in a pest insect has recently been discovered and is the focus of this application. The broad, long-term objectives are to understand this pheromonotropic hormone's mode of action, receptor interactions, factors regulating its processing, secretion, and eventually the structure and regulation of its encoding gene. These data could lead to the development of novel pest control tactics, such as incorporating the gene encoding this peptide into an insect-specific baculovirus to enhance the pathology of infection. Also, knowledge of the mechanisms of transcription, translation, or precursor processing could lead to the development of specific inhibitors that interfere with these processes. The pheromonotropic peptide is released from the bursae copulatrix of the redbanded leafroller moth. With the recent characterization of its structure, the stage is set to initiate research on the following specific aims: 1) To study structure-activity relationships of synthetic pheromonotropic bursa peptide, various truncated peptides and analogs as a basis for determining 3-dimensional conformation requirements in receptor interactions. Materials will be tested in an isolated abdomen bioassay over a range of doses to determine their relative potency and efficacy; 2) To study the receptor sites and mode of action for the pheromonotropic bursa peptide, as well as for PBAN, which stimulates the release of the bursa peptide. Various structural, photolabile, and radioactive analogs of the peptides will be synthesized and used to localize receptor proteins by photoaffinity labeling. A working model will guide research on the mode of action and interaction of the two peptides. The research will investigate the involvement of second messengers by testing activities of various compounds in two bioassay systems, along with an RIA and an ELISA; 3) To determine in an immunohistochemical study, the distribution of cells in the bursa and ovaries that synthesize the pheromonotropic peptide; and 4) To isolate and characterize the gene encoding the pheromonotropic bursa peptide, as well as to determine the temporal and spatial patterns of its expression. This study will utilize degenerate oligonucleotide primers for use in PCR experiments, and in situ hybridization in conjunction with immunocytochemical techniques.